I played with the hot .22s for several years, but mostly for coyotes and deer/exotics. I used the Federal Premium load with the 55gr Trophy Bonded for Blackbuck, mule deer, axis deer and coyotes in a .220 Swift (Mod 700 classic barrel set on a Mod 7 action) I then used the 22-250AI in a 9" twist, and a 224 TTH in an 8" twist. I used it on coyotes and one huge hog with the 75gr Swift. 6mm brass seems to be unavailable around here anymore though. Have a good smith run a borescope in your barrel to see if its even worth setting back/rechambering/refreshing. It may be "fire-checked" the entire bore. The problem then is you start tearing up your bullets, fouling stays bad, accuracy is shot. I don't know anything about the 22 Creedmoor, but it "sounds" like a good one to play with! Have a ball pard!